The present invention relates, in general, to a tensioning or deflection pulley for a belt drive.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
German patent publication DE 32 40 075 A1 describes a tensioning or defection pulley having a wheel disk which is rotatably mounted via a sealed rolling-contact bearing to a carrier. The wheel disk has a double-T-shaped cross section with an inner ring and an outer ring, which are interconnected by a center bridge formed with recesses that are separated from one another by ribs. The pulley is provided on its carrier-distal side with a cap cover which snaps onto the inner ring of the wheel disk. This conventional pulley suffers shortcomings arising from ingress of dirt because the sliding seals that are integrated in the rolling-contact bearing are unable to fully protect the interior. Dirt can thus migrate into the bearing region of the pulley and thereby significantly reduce the operating life of the pulley.
German patent publication DE 37 19 479 A1 describes a combined driving and tensioning pulley which is closed on one side by a snap-on lid and is provided on the other side with a lip seal in sliding contact upon a surface of a machine part. This type of pulley is also endowed with drawbacks and shortcomings relating to the need to conform the lip seal to the pertaining attachment structure, or for example to the effect that is hoped to be obtained but may not always be realized.
It would therefore be desirable and advantageous to provide an improved tensioning or deflection pulley to obviate prior art shortcomings and to provide superior protection of the bearing space.